NSCell

Inherits From: NSObject

Conforms To: NSCoding, NSCopying NSObject (NSObject)

Declared In: AppKit/NSCell.h

Class Description

The NSCell class provides a mechanism for displaying text or images in an NSView without the overhead of a full NSView subclass. In particular, it provides much of the functionality of the NSText class by providing access to a shared NSText object used by all instances of NSCell in an application. NSCells are also extremely useful for placing titles or images at various locations in a custom subclass of NSView.

NSCell is used heavily by most of the NSControl classes to implement their internal workings. For example, NSSlider uses an NSSliderCell, NSTextField uses an NSTextFieldCell, and NSBrowser uses an NSBrowserCell. Sending a message to the NSControl is often simpler than dealing directly with the corresponding NSCell. For instance, NSControls typically invoke updateCell: (causing the cell to be displayed) after changing a cell attribute; whereas if you directly call the corresponding method of the NSCell, the NSCell might not automatically display itself again.

Some subclasses of NSControl (notably NSMatrix) allow multiple NSCells to be grouped and to act together in some cooperative manner. Thus, with an NSMatrix, a group of radio buttons can be implemented without needing an NSView for each button (and without needing an NSText object for the text on each button).

The NSCell class provides primitives for displaying text or an image, editing text, formatting floating-point numbers, maintaining state, highlighting, and tracking the mouse. NSCell's method trackMouse:inRect:ofView:untilMouseUp: supports the target object and action method used to implement controls. However, NSCell implements target/action features abstractly, deferring the details of implementation to subclasses of NSActionCell.

The initImageCell: method is the designated initializer for NSCells that display images. The initTextCell: method is the designated initializer for NSCells that display text. Override one or both of these methods if you implement a subclass of NSCell that performs its own initialization. If you need to use target and action behavior, you may prefer to subclass NSActionCell, which provides the default implementation of this behavior.

For more information on how NSCell is used, see the NSControl class specification.

Initializing an NSCell

• - (id)initImageCell:(NSImage *)anImage Initializes a new NSCell with the NSImage anImage.
• - (id)initTextCell:(NSString *)aString Initializes a new NSCell with title aString.

• - (void)calcDrawInfo:(NSRect)aRect Implemented by subclasses to recalculate drawing sizes.
• - (NSSize)cellSize Returns the minimum size needed to display the NSCell.
• - (NSSize)cellSizeForBounds:(NSRect)aRect Returns the minimum size needed to display the NSCell.
• - (NSRect)drawingRectForBounds:(NSRect)theRect Returns the rectangle the NSCell draws in.
• - (NSRect)imageRectForBounds:(NSRect)theRect Returns the rectangle that the cell's image is drawn in.
• - (NSRect)titleRectForBounds:(NSRect)theRect Returns the rectangle that the cell's title is drawn in.

• - (void)setType:(NSCellType)aType Sets the NSCell's type to aType.
• - (NSCellType)type Returns the NSCell's type.

• - (void)setState:(int)value Sets the state of the NSCell to value (0 or 1).
• - (int)state Returns the state of the NSCell (0 or 1).

• - (BOOL)isEnabled Returns whether the NSCell reacts to mouse events.
• - (void)setEnabled:(BOOL)flag Sets whether the NSCell reacts to mouse events.

• - (NSImage *)image Returns the NSCell's image.
• - (void)setImage:(NSImage *)anImage Makes anImage the NSCell's image.

• - (double)doubleValue Returns the NSCell's value as a double.
• - (float)floatValue Returns the NSCell's value as a float.
• - (int)intValue Returns the NSCell's value as an int.
• - (NSString *)stringValue Returns the NSCell's value as a string.
• - (void)setDoubleValue:(double)aDouble Sets the NSCell's value to aDouble.
• - (void)setFloatValue:(float)aFloat Sets the NSCell's value to aFloat.
• - (void)setIntValue:(int)anInt Sets the NSCell's value to anInt.
• - (void)setStringValue:(NSString *)aString Sets the NSCell's value to a copy of aString.

• - (void)takeDoubleValueFrom:(id)sender Sets the NSCell's value to sender's double floating-point value.
• - (void)takeFloatValueFrom:(id)sender Sets the NSCell's value to sender's floating-point value.
• - (void)takeIntValueFrom:(id)sender Sets the NSCell's value to sender's integer value.
• - (void)takeStringValueFrom:(id)sender Sets the NSCell's value to sender's string value.

• - (NSTextAlignment)alignment Returns the alignment of text in the NSCell.
• - (NSFont *)font Returns the Font used to display text in the NSCell.
• - (BOOL)isEditable Returns whether the NSCell's text is editable.
• - (BOOL)isSelectable Returns whether the NSCell's text is selectable.
• - (BOOL)isScrollable Returns whether the NSCell scrolls to follow typing.
• - (void)setAlignment:(NSTextAlignment)mode Sets the alignment of text in the NSCell to mode.
• - (void)setEditable:(BOOL)flag Sets whether the NSCell's text is editable.
• - (void)setFont:(NSFont *)fontObject Sets the Font used to display text in the NSCell to fontObject.
• - (void)setSelectable:(BOOL)flag Sets whether the NSCell's text is selectable.
• - (void)setScrollable:(BOOL)flag Sets whether the NSCell scrolls to follow typing.
• - (NSText *)setUpFieldEditorAttributes:(NSText *)textObject Sets NSText parameters for the field editor. (See the documentation for NSText.)
• - (void)setWraps:(BOOL)flag Sets whether the NSCell's text is word-wrapped.
• - (BOOL)wraps Returns whether the NSCell's text is word-wrapped.

• - (void)editWithFrame:(NSRect)aRect Allows text editing in response to a mouse-down event. inView:(NSView *)controlView editor:(NSText *)textObject delegate:(id)anObject event:(NSEvent *)theEvent
• - (void)endEditing:(NSText *)textObject Ends any text editing occurring in the NSCell.
• - (void)selectWithFrame:(NSRect)aRect Allows text selection in response to a mouse-down event. inView:(NSView *)controlView editor:(NSText *)textObject delegate:(id)anObject start:(int)selStart length:(int)selLength Validating Input
• - (int)entryType Returns the type of data the user can type into the NSCell.
• - (BOOL)isEntryAcceptable:(NSString *)aString Returns whether aString is acceptable for the entry type.
• - (void)setEntryType:(int)aType Sets the type of data the user can type into the NSCell.

• - (void)setFloatingPointFormat:(BOOL)autoRange Sets the display format for floating-point values. left:(unsigned int)leftDigits right:(unsigned int)rightDigits Modifying Graphic Attributes
• - (BOOL)isBezeled Returns whether the NSCell has a bezeled border.
• - (BOOL)isBordered Returns whether NSCell has a plain border.
• - (BOOL)isOpaque Returns whether the NSCell is opaque.
• - (void)setBezeled:(BOOL)flag Sets whether the NSCell has a bezeled border.
• - (void)setBordered:(BOOL)flag Sets whether the NSCell has a plain border.

• - (int)cellAttribute:(NSCellAttribute)aParameter Returns various flag values.
• - (void)setCellAttribute:(NSCellAttribute)aParameter to:(int)value Sets various NSCell flags.

• - (NSView *)controlView Implemented by subclasses to return the NSView last drawn in (normally an NSControl).
• - (void)drawInteriorWithFrame:(NSRect)cellFrame Draws the area within the NSCell's border in controlView. inView:(NSView *)controlView
• - (void)drawWithFrame:(NSRect)cellFrame Draws the entire NSCell in controlView. inView:(NSView *)controlView
• - (void)highlight:(BOOL)lit If lit is YES, highlights the NSCell in controlView, withFrame:(NSRect)cellFrame otherwise unhighlights. inView:(NSView *)controlView
• - (BOOL)isHighlighted Returns whether the NSCell is highlighted.

• - (SEL)action Implemented by subclasses to return the action method.
• - (BOOL)isContinuous Returns whether the NSCell continuously sends the action.
• - (int)sendActionOn:(int)mask Determines when the action is sent while tracking.
• - (void)setAction:(SEL)aSelector Implemented by subclasses to set the action method.
• - (void)setContinuous:(BOOL)flag Sets whether the NSCell continuously sends the action.
• - (void)setTarget:(id)anObject Implemented by subclasses to set the target object.
• - (id)target Implemented by subclasses to return the target object.

• - (void)setTag:(int)anInt Implemented by subclasses to set an identifier tag.
• - (int)tag Implemented by subclasses to return the identifier tag.

• - (NSString *)keyEquivalent Implemented by subclasses to return a key equivalent.

• + (BOOL)prefersTrackingUntilMouseUp Returns NO, so tracking stops when the mouse leaves the NSCell; subclasses may override.
• - (BOOL)continueTracking:(NSPoint)lastPoint Returns whether tracking should continue based on at:(NSPoint)currentPoint lastPoint and currentPoint within controlView. inView:(NSView *)controlView
• - (int)mouseDownFlags Returns the event flags set at the start of mouse tracking.
• - (void)getPeriodicDelay:(float *)delay Returns repeat values for continuous sending of the action. interval:(float *)interval
• - (BOOL)startTrackingAt:(NSPoint)startPoint Determines whether tracking should begin based on inView:(NSView *)controlView startPoint within controlView.
• - (void)stopTracking:(NSPoint)lastPoint Allows the NSCell to update itself to end tracking, based on at:(NSPoint)stopPoint lastPoint and stopPoint within controlView; flag is YES inView:(NSView *)controlView if this method was invoked because the mouse went up. mouseIsUp:(BOOL)flag
• - (BOOL)trackMouse:(NSEvent *)theEvent Tracks the mouse, returning YES if the mouse goes up inRect:(NSRect)cellFrame while in cellFrame. This method is usually invoked by ofView:(NSView *)controlView an NSControl's mouseDown: method, which passes untilMouseUp:(BOOL)flag the mouse-down event in theEvent. If flag is YES, the method keeps tracking until the mouse goes up; otherwise it tracks until the mouse leaves cellFrame.

• - (void)resetCursorRect:(NSRect)cellFrame Sets text NSCells to show the I-beam cursor. inView:(NSView *)controlView Comparing to Another NSCell
• - (NSComparisonResult)compare:(id)otherCell Compares the string values of this cell and otherCell (which must be a kind of NSCell). Raises NSBadComparisonException if otherCell is not of the NSCell class.

• - (id)representedObject Returns the object that the receiver represents, if any. - (void)setRepresentedObject:(id)anObject Creates an association between the receiver and anObject. anObject will be retained, released, archived, and unarchived whenever the receiver is. If another cell is already associated with anObject, that association is broken, and the receiver is associated with the object.